In the most existing mobile communication systems, such as Global System for Mobile Communications (GSM), Wideband Code Division Multiple Access Wireless (WCDMA), Code Division Multiple Addressing (CDMA), Worldwide Interoperability for Microwave Access (WiMAX), CDMA2000, TD-SCDMA, Long Term Evolution (LTE), WLAN/WiFi and other wireless communication systems, when a terminal initiates an uplink service, a random access process is performed firstly. At this time, since there may be several terminals to initiate random accesses simultaneously and to choose the same access chance and access code, it will cause an access collision, thus bringing an access failure of this time, and the access failure will cause an increased access delay and decreased access success rate. In current mobile communication systems, more resources are generally allocated, so as to make a lower collision probability to ensure time delay and access success rate of access.
With the development of mobile communication, Machine to Machine (M2M) communication appears, while Internet of Things (IOT) means an application of M2M in a wide area network, particularly, in a mobile operator's network, namely a radio data transmission service which is used to service the Machine to Machine through a special trade terminal by taking a mobile network operator's wireless network as a platform and adopting multiple transmission manners (e.g., CDMA, GSM and so on). The M2M/IOT has a wide field of application, which may be applied to various scenes, such as intelligent transport, telemedicine, monitor and control, smart grid, environmental detection, smart homes and so on. At present, the M2M and Internet of Things become a hot point for the operators, and various applications based on the M2M and Internet of Things are developing rapidly. Unlike the previous Human to Human (H2H) communication, M2M communication has a larger amount of terminals, which can achieve ten times of H2H communication terminals, or even more, for example, about magnitude of 50 billion.
Machine Type Communication (MTC) means network communication (i.e., M2M application) performed without human's participation between one or more network elements, for example, applications such as traffic control and management, factory monitor and control, and remote meter reading, etc. In an M2M application, multiple Machine to Machine Equipments (M2ME) with a same M2M application form a whole, which is called Group for short.
Machine type communication device identity shall uniquely identify one M2M terminal, which may be International Mobile Subscriber Identity (IMSI), Mobile Station International ISDN Number (MSISDN), IP Address (IP addr), IP Multimedia Public Identity (IMPU), IP Multimedia Private Identity (IMPI) and the like.
Corresponding time and frequency resources are only allocated when a user needs to communicate, because of limitations of wireless communication resources. When a user needs to initiate communication, a random access process is performed firstly, then Radio Resource Control (RRC) connection setup and data transmission are further performed, and lastly, the occupied resources are released when the communication is finished. Taking LTE as an example, the random access resources includes two parts, one being a slot and frequency on which the random access is initiated and the other being a used Preamble (Preamble). In the existing cell radio communication system, random access is performed two ways, namely, a contention based way and a non-contention based way.
The non-contention based random access way means that an eNodeB (eNB) informs a User Equipment (UE) to use its own unique access resources. Since the access resources need to be allocated by the eNB, it needs larger system overhead and is generally used in a scene with a high demand on time delay, such as when handover or drop-call occurs.
In the contention based random access way, an eNB points out, in a broadcast message, the information of the access resources on which a random access is allowed to be initiated in the present cell. Then a UE selects one allowed Preamble randomly, selects random access frequency resources at next one moment at which the random access is allowed, and then initiates a random access at the selected random access time and frequency position. Since each UE selects random access resources independently and randomly, when multiple UEs select the same random access resources, a conflict will occur. According to a conflict solving scheme in the existing protocol, at most one of the multiple UEs to which the conflict occurs can make a successful access, while all other UEs initiate access attempt again only after backing off a period of time and backs off again when the conflict occurs again until they make a successful access or a maximum value of access attempts is reached. The conflict will prolong the access time of terminals and bring extra burdens to the network and terminals.
However, the amount of terminals participating in M2M communication is very large, while the interaction flow rate of each terminal may be very small and the interaction may be abrupt. The function realized by the M2M terminal (also called MTC terminal), which only needs to implement some special information transmission interaction, is relatively single. Positions of some terminals may be relatively fixed, or may not be often changed. Actions of M2M terminals under one special application are consistent.
In an M2M service, since the amount of MTC terminals is very large, if a large amount of MTC terminals access the network and contend for network resources, new burden will be brought to the network, especially in some application scenes, such as intelligent meter reading service.
Taking intelligent transportation as an example, one typical intelligent transport system includes a GPS (Globe Positioning System)/GLONASS (Global Navigation Satellite System) satellite positioning system, a mobile vehicle terminal, a radio network and intelligent transport systems (ITS) control center. The vehicle terminal receives ranging information of a navigation satellite network through a GPS module, and transfers information, such as, longitude, latitude, speed, time of vehicle and the like, to a microcontroller. The vehicle state information is collected by a video imaging device. The microcontroller performs a bidirectional information interaction with an ITS control center through a GPRS module to complete functions, such as, vehicle monitor and control, etc.
In another example, taking the smart grid as an example, the smart grid needs all smart grid terminals to report data periodically. For example, for electronic meter reading service, all smart grid terminals report data to a certain special server at a certain special time. For example, many national intelligent grids require a large amount of MTC terminals to transmit uplink meter reading data frequently in a 5-minute cycle, and the data amount of meter reading data is small.
In the existing network, a dedicated signaling connection and a dedicated data bearer need to be established for a terminal to transmit uplink data, and the network needs to allocate a dedicated Cell Radio Network Temporary Identity (C-RNTI) to each terminal. After transmitting the uplink data completely, the UE releases the Radio Resource Control (RRC) connection and enters an IDLE state.
For example, in the application scene of intelligent monitor and control or that of measurement, a large amount of MTC terminals need to report a data packet with a small amount of data periodically and frequently, and when transmitting data each time, a large amount of MTC terminals establish signaling connection and data radio bear, thus bringing a large signaling overhead and consuming a large amount of network resources.
In order to overcome the issue of large signaling overhead brought by this frequent state transition, in the prior art, an MTC terminal may be always kept in a connective state, but if the MTC terminal is always kept in the connective state, a large amount of network configuration resources, such as C-RNTI, are occupied.
In addition, in the prior art, if an H2H communication is adopted, one cell needs to support 16K (14 bits) users, and it will bring the lack of C-RNTI if an MTC terminal is introduced.
Therefore, in the M2M communication, when an MTC terminal transmits data frequently and periodically, frequently establishing signaling connections and data bearers will bring large signaling overhead and may cause the lack of C-RNTI.